This invention relates to a hearing aid in which acoustic feedback is controlled.
Acoustic feedback, a common problem in both in-the-ear and behind-the-ear hearing aids, can be eliminated in some users by placement of a capacitor in parallel with the hearing aid amplifier output. However, this does not allow adjustments at the time of fitting the hearing aid and therefore, feedback cannot be eliminated in all users.
A high frequency cutoff circuit can be used to eliminate feedback, but it also entirely eliminates the high frequency response of the hearing aid.
Accurate ear impressions coupled with precise duplication at the laboratory can provide a precise fit for the hearing aid which is helpful in reducing feedback. However, often the hearing aid must be returned to the laboratory for minor corrections due to inaccuracies in the original impressions or in the duplications.